From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Yang, Xiaowei" <xiaowei.yang@intel.com>
Subject: Re: Memory allocation in NUMA system
Date: Fri, 25 Jul 2008 15:51:38 +0800
Message-ID: <4889860A.1040201@intel.com>
References: <C4AF3EDB.1B8D9%keir.fraser@eu.citrix.com>
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To: Keir Fraser <keir.fraser@eu.citrix.com>
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Keir Fraser wrote:
> On 25/7/08 08:22, "Yang, Xiaowei" <xiaowei.yang@intel.com> wrote:
> 
>  >> Doesn't your solution amount to what we already do, for the 2-node 
> example?
>  >> i.e., node0 would not be chosen until node1 is exhausted?
>  >>
>  > Oh, what I mean is:
>  > With the above possible fix, the domain memory is allocated from the
>  > node it pinned to. As node0's memory is precious for DMA, it's suggested
>  > to pin VMs to other nodes firstly.
>  >
>  > And for non-pinned VM, we can stick to the original method.
> 
> How about by default we guarantee no more than 25% of a node's memory is
> classed as 'DMA memory', and we reduce the DMA address width variable in Xen
> to ensure that?
> 
> So, in your example, we would reduce dma_bitsize to 30.
> 
>  -- Keir
> 
> 
Yes, a good suggestion!

Thanks,
Xiaowei